Scalable wlan gateway

ABSTRACT

A technique for combining transmission bandwidths of several communication devices, such as mobile stations (MS1, MS2) is disclosed. A master mobile station (MS1) establishes ( 7 - 0 ) a WLAN access point communicating with WLAN client terminals (CT). One or more slave mo-bile stations (MS2) may detect a predefined network identifier and join the WLAN network. The master (MS1) as-signs IP addresses for the client terminals (CT) and slave mobile stations (MS2). The master also resolves DNS queries in cooperation with external DNS servers. Traffic, including internet packets (IP1-IP4), between the client terminals and various internet hosts (HO) is tunneled over multiple simultaneous transmission paths ( 7 - 6, 7 - 8; 7 - 18, 7 - 22 ) between the master (MS1) and a multiplexing/demultiplexing computer (SM). The inventive band-width combination technique is transparent to the client terminals (CT) and the internet hosts (HO).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 15/710,405 filed on Sep. 20, 2017, which is acontinuation application of U.S. patent application Ser. No. 13/924,110,filed on Jun. 21, 2013, now U.S. Pat. No. 9,883,487, which is acontinuation application of U.S. patent application Ser. No. 13/240,468,filed on Sep. 22, 2011, now U.S. Pat. No. 8,493,951, which is acontinuation of U.S. patent application Ser. No. 12/336,279, filed onDec. 16, 2008, now U.S. Pat. No. 8,064,418. The InternationalApplication claims priority to Finnish Patent Application No. 20080345,filed May 9, 2008, all of which are hereby incorporated by reference intheir entirety.

FIELD OF THE INVENTION

The invention relates to methods, apparatuses and software products forproviding a wireless broadband internet connection via a mobilecommunication network. In the context of the present invention, abroadband connection means a connection capable of transmitting traffic,in good network conditions, faster than a V.90 modem can, or faster than64 kilobits per second.

BACKGROUND OF THE INVENTION

Wireless broadband modems can be used to couple personal computers orclient terminals to the internet in places where wired internetconnections or local-area networks are not available. Prior art wirelessbroadband modems exhibit certain problems. For instance, sharing asingle wireless broadband connection among several users (clientterminals) is awkward at best. Normally this requires setting up one ofseveral client terminals as a master terminal that provides the internetconnection to the remaining client terminals. This process consumesresources of the master terminal and the client terminals cannot operatewithout the master. The difficulty of sharing a single wirelessbroadband connection among several users is understandable in view ofthe fact that most wireless broadband modems are given or sold at anominal cost by mobile network operators in connection with a networksubscription. The network operators' obvious desire is to sell asubscription to each user instead of sharing a single connection amongseveral users. Another problem of prior art wireless broadband modems isthe fact that most of them are “wireless” only towards the mobilenetwork and the connection to the client terminal takes place via a USBcable. The wired connection is actually a benefit in connection withfixed client terminals, such as home computers, because the wiredconnection can also supply power to the wireless broadband modem, but inconnection with mobile client terminals, the wired nature of the USBconnection is a definite handicap. Yet another problem is that thebandwidth provided by the mobile station and access network may beinsufficient, particularly when several client terminals share a singlewireless broadband connection.

SUMMARY OF THE INVENTION

An embodiment of the present invention provides a mobile station. Themobile station provides network access over a wireless local areanetwork (WLAN) for a WLAN client terminal with a second mobile station.The mobile station comprises a memory for storing applications, aprocessor coupled with the memory for executing applications storedthereon, a WLAN circuitry for establishing the WLAN, and an applicationstored on the memory including instructions executable to the processor.The instructions that when executed instruct the processor to activatethe WLAN; receive, from the WLAN client terminal via the WLAN, a firstdata packet including address information of a internet host; forwardthe first data packet to the second mobile station via the WLAN; andinstruct the second mobile station to send the first data packet to theinternet host according to the address information.

Another embodiment of the present invention provides a method. Themethod is executed by a mobile station for providing network access overa wireless local area network (WLAN) to a WLAN client terminal. Themethod comprises: establishing a WLAN; receiving, from the WLAN clientterminal via the WLAN, a first data packet including address informationof a internet host; forwarding the first data packet to a second mobilestation via the WLAN; and instructing the second mobile station to sendthe first data packet to the internet host according to the addressinformation.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention will be described in greater detail bymeans of specific aspects and embodiments with reference to the attacheddrawings, in which:

FIG. 1 is a schematic view of a general network architecture in whichthe invention can be used;

FIG. 2 shows a mobile station configured for use in a scalable WLANgateway;

FIG. 3 shows a block diagram of a ShareMachine computer;

FIG. 4 shows a block diagram of a SuperHead computer;

FIG. 5 is a signaling diagram illustrating a gateway establishment in ascenario which comprises a WLAN client terminal, a mobile stationconfigured as a gateway, a DNS server and an internet host;

FIG. 6 is a signaling diagram illustrating IP address discovery and DHCPoperation, which involves a WLAN client terminal, a master gateway and aslave gateway;

FIG. 7 is a signaling diagram illustrating a flow of data packets from aWLAN client terminal to an internet host via a master gateway, a slavegateway and a ShareMachine computer;

FIG. 8 is a more detailed signaling diagram illustrating data flow froma WLAN client terminal to an internet host via a master gateway, a slavegateway and a ShareMachine computer;

FIG. 9 discloses a procedure that the master mobile station may utilizeto discover serving SuperHead and ShareMachine computers

FIG. 10 shows an embodiment in which the gateway application in themobile station is activated automatically in response to detection of anearby WLAN client terminal;

FIG. 11 shows an embodiment in which the mobile station'slocation-determination functionality is used to enhance image uploadingto an image hosting server.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 is a schematic view of a general network architecture in whichthe invention can be used. Reference documents 1 and 2 (commonly ownedpatent applications, unpublished at the filing date of the presentapplication, which is why some key sections of their contents arerepeated here) disclose a technique in which mobile station MSestablishes an ad-hoc WLAN network WN and acts as a gateway forproviding a single communication path between one or more clientterminals CT and an internet host HO. The communication path extends viaan access network AN1 and a data network DN to the host HO. It is thepurpose of the present invention to provide a mobile station MS which isoperable to establish a scalable gateway between one or more clientterminals CT, each of which communicates with a respective internethost.

As used herein, a gateway means an interface point between one or moreWLAN client terminals on one hand and one or more mobile access networkson the other hand. A scalable gateway means a gateway arrangement whichis capable of providing a dynamically varying number of simultaneousparallel transfer paths over one or more mobile access networks, suchthat data packets belonging to the same internet connection between aclient terminal) and the host are multiplexed (combined) anddemultiplexed (divided) at the ends of the simultaneous paralleltransfer paths.

According to the present invention, the scalable gateway is establishedand managed by a master mobile station MS1. The scalable gatewayestablished by the master mobile station MS1 may be subsequently joinedand supported by zero or more slave mobile stations MS2. A slave mobilestation MS2, when present, may join the WLAN network WN established bythe master mobile station MS1 and support its operation by providingmultiple radio interface paths, thus increasing bandwidth. Slave mobilestations MS2 may also detach from the gateway without causing any otherharm than a corresponding reduction in bandwidth. The expression “zeroor more slave mobile stations” means that the master mobile station MS1can provide gateway operations by itself, but increased bandwidth may beprovided by one or more slave mobile stations MS2.

The master and slave mobile stations MS1, MS2 can be identical in termsof hardware and software, and any mobile station in which the inventivescalable gateway application is executed first checks if an ad-hoc WLANnetwork is already established by another mobile station. For example,WLAN networks offering the inventive gateway functionality can bedetected on the basis of the WLAN SSID identifier. If the mobile stationdetects an already-established WLAN network, it assumes the role of aslave mobile station. If an already-established ad-hoc WLAN network isnot detected, the inventive mobile station establishes the WLAN networkitself and assumes the role of the master mobile station for that WLANnetwork. For reasons of clarity, FIG. 1 shows only one slave mobilestation MS2, but the invention is not restricted to any particularnumber of mobile stations.

The invention is ideally implemented such that the master mobile stationMS1 and slave mobile station(s) MS2 are coupled to different basestations BS1, BS2, . . . . Operation via multiple different basestations helps ensure that the cellular radio interfaces between mobilestations and base stations do not constitute bottlenecks. For instance,such coupling to different base stations can be ensured by providing thevarious mobile stations MS1, MS2 with SIM cards (Subscriber IdentityModule) of different access network operators. The access networks AN1,AN2 typically comprise gateway GPRS support nodes GGSN1, GGSN2 forconnecting to data networks DN, such as the internet.

Because different packets transmitted between a client terminal CT and ahost HO may be propagated via multiple base stations BS1, BS2 and accessnetworks AN1, AN2, rules and schemes for packet routing must be defined.For instance, it must be decided whether packets transmitted via themultiple base stations and access networks are routed at the clientterminal(s) CT or the mobile station(s) MS1, MS2. Currently there arecommercially available mobile stations, which are provided with WLANclient software, and one way to implement packet routing is to performthe routing in the client terminal(s) CT, such that a transmittingclient terminal sends packets to the first available mobile station, thenext packet to the next available mobile station, and so on. A benefitof this routing scheme is that it eliminates packet forwarding among themobile stations. On the other hand, implementing the packet routing inthe client terminal(s) requires modifications to the protocol stacks inthe client terminal(s), which is why the present invention is based onthe idea that packet routing via the multiple mobile stations MS1, MS2is performed in the mobile stations. Performing packet routing in themobile stations provides the benefit that the scalable gateway is almostcompletely transparent to the client terminal(s), and—as seen from theclient terminal(s)—the only change caused by the invention is increasedbandwidth.

It is worth noting that performing packet routing in the mobile stationsis far from trivial, however. This means that the mobile stations mustsend, or they should send, individual packets to one another. But alarge portion of currently available smart telephones are based onSymbian.RTM. 60 or 80 platforms, and current implementations ofSymbian.RTM. 60 or 80 platforms do not support it. In other words,mobile stations based on Symbian.RTM. 60 or 80 platforms cannot sendindividual packets to one another over the WLAN network. This limitationcould be overcome by performing the packet routing in the clientterminal(s) but, as stated earlier, this requires modifications to theprotocol stacks. The inventor has found out, however, that it is notnecessary to send the packets as point-to-point transmissions, and thelimitation of Symbian.RTM. 60 or 80 platforms can be overcome by sendingthe packets in multicast transmissions, as will be explained in moredetail in connection with FIGS. 7 and 8.

FIG. 1 shows a simplified network architecture in the sense that onlyone specimen of most elements is displayed. In practice, there will beseveral ad-hoc WLAN networks WN, each comprising one master mobilestation MS1 and a varying number of slave mobile stations MS2. Eachad-hoc WLAN network WN supports a varying number of client terminals CT,each of which may have multiple internet connections to various internethosts HO. This means that there is a many-to-many mapping among severalof the network elements. The invention is implemented such that itsoperation is transparent to the ends of the connections, that is, to theclient terminals and the hosts, and any multiplexing and demultiplexingoperations (necessitated by the scalability) are performed by the mastermobile stations MS1 and multiplexing/demultiplexing computers, which arecalled ShareMachine computers SM. The primary task of the SuperHeadcomputers is to keep track of available ShareMachine computers SM.

Various measures may be taken to enhance data security and overallsystem robustness. For instance, virtual private network (VPN)technology may be utilized for some legs of the connections between theclient terminals CT and the internet hosts HO. In one implementation, aVPN is established for each connection section between a mobile stationMS1, MS2 and a ShareMachine computer SM. In this implementation theclient terminals CT and the internet hosts HO do not need to establishthe VPN and, apart from the increased bandwidth, the invention istransparent to them. System robustness may be enhanced by implementingthe ShareMachine and SuperHead computers SM, SH in a distributed manner,as will be explained in detail in connection with FIG. 9.

FIG. 2 shows a mobile station configured for use in a scalable WLANgateway. The description of the mobile station begins by describing howa mobile station can act as a unitary (non-scalable) gateway. Such agateway operation is described in reference documents 1 and 2 (commonlyowned, unpublished applications).

For acting as a unitary (non-scalable) gateway, the mobile station MScomprises a central processing unit CP 205 and memory 210. In addition,the mobile station MS comprises or utilizes external input-outputcircuitry 215 which constitutes the mobile station's user interface andcomprises an input circuitry 220 and an output circuitry 225. The inputcircuitry 220 comprises the mobile station's microphone and user-inputdevice, such as a keypad and/or touch screen. The output circuitry 225comprises the mobile station's display and earphone or loudspeaker. Themobile station MS further comprises reception/transmission circuitry 230which comprises a transmission circuitry 235, reception circuitry 240and antenna 245. A subscriber identity module, SIM, 250 is used by anauthentication function 260 to authenticate the mobile station user andto identify the user's subscription to the access network. The mobilestation also comprises WLAN (Wireless Local Area Network) circuitry 255whose normal mode of usage is acting as a WLAN client to a WLAN basestation (not shown).

In order to support installable program modules, the mobile station'smemory MEM 210 may comprise routines for downloading installable programmodules and for storing the installable program modules in the memoryMEM for execution by the central processing unit CP. FIG. 1 shows anarrangement in which the mobile station is configured to downloadinstallable program modules from a repository RP via a data network DN,an access network AN, the antenna 245 and reception circuitry 240,although other arrangements are equally possible, such as downloadingthe installable program modules via the data network DN to a clientterminal CT, from which the installable program modules are transferredto the mobile station the WLAN circuitry 255 or via some othershort-range connection, such as Bluetooth or Universal Serial Bus (USB,not shown separately). The access network AN is typically a broadbandcapable mobile communication network, while the data network DN istypically the internet or some closed subnetwork implementing internetprotocol (IP), commonly called intranets or extranets. At this level ofgeneralization, all previously-discussed elements of FIG. 1 can beconventional as used in the relevant art. One or more external hosts areaccessible via the access network AN and data network DN, as will bedescribed in more detail below. Finally, reference numeral 280 denotesan area of the memory 210 used to store parameters and variables.

The foregoing description of FIG. 1 describes an applicable mobilestation in technical terms. Such mobile stations are commerciallyavailable: For instance, at the priority date of the present invention,mobile stations based on Symbian S60 or S80 platforms can be used,provided that they support WLAN and broadband communications. Adeparture from prior art mobile stations can be seen in the fact thatthe mobile station comprises the inventive gateway application 270,either as a factory-installed software application or as a downloadableapplication. The client terminals CT resemble laptop computers or smarttelephones, but those skilled in the art will realize that the mobilestation MS provided with the inventive gateway application 270 supportsvirtually any client terminal capable of acting as a WLAN client,personal digital assistants, home entertainment devices, digitalcameras, etc., to name just a representative sample of applicable devicetypes.

Within the gateway application 270, reference numeral 272 collectivelydenotes program-implemented functions which are used to operate themobile station as a non-scalable gateway which provides one radiointerface to one or several client terminals. These functions, whichwill be described in connection with FIG. 5, include establishment of anad-hoc WLAN network, generation of a beacon ID, IP address assignmentand discovery (eg DHCP), domain name services (DNS) in cooperation withexternal domain name servers, multi-protocol support and roamingsupport. The multi-protocol support functionality may include a NetworkAddress & Port Translation (NAPT) block which translates the source anddestination addresses. Translation of port numbers may be used toidentify various connections to or from the same IP address. A detailedconversion example will be described in connection with FIG. 8.

Reference numeral 274 collectively denotes program-implemented functionswhich are used to operate the mobile station as a scalable gateway whichcoordinates provision of multiple radio interfaces to one or severalclient terminals. These functions, which will be described in connectionwith FIGS. 6 through 8, include a multicasting function, which includespacket multicast transmission and signaling in the WLAN network, packetdelivery and signaling between a master mobile station and a slavemobile station, and a communication function for communicating withSuperHead and ShareMachine computers.

FIG. 3 shows a block diagram of a multiplexing/demultiplexing computerwhich, in the context of the present invention, is called a ShareMachinecomputer SM. It comprises a central processing unit CP 305 and memory310, as well as a network interface 330 for communicating with datanetworks DN, such as the internet. The ShareMachine computer SM alsocomprises or utilizes external input-output circuitry 315 whichconstitutes the ShareMachine computer's user interface and comprises aninput circuitry 320 and an output circuitry 325.

The nature of the user interface depends on which kind of computer isused to implement the ShareMachine computer SM. If the ShareMachinecomputer is a dedicated computer, it may not need a local userinterface, such as a keyboard and display, and the user interface may bea remote interface, wherein the ShareMachine computer is managedremotely, such as from a web browser over the internet, for example. Onthe other hand, it is expected that some access network operators maydisplay a hostile attitude to the present invention in general and theShareMachine computers in particular, because the present inventionmakes it possible to share one or a few access network subscriptionsamong a larger number of client terminals. Thus some network operatorsmay attempt to block the operation of the ShareMachine computers. Inorder to improve the robustness of the invention, a relatively largenumber of potential ShareMachine computers may be involved. Conventionalhome computers are prime examples of potential ShareMachine computers.In that case, the user interface should be a local interface, includinga display, keyboard and pointing device, although for the purposes ofthe present invention, the user interface is primarily needed to launchthe software application 370 which makes an appropriate computer(hardware-wise) into the inventive ShareMachine computer. In addition,the user interface may be utilized for obtaining traffic statistics.Reference numeral 380 denotes an area of the memory 310 used to storeparameters and variables.

The ShareMachine computer's software application 370 comprises programcode for instructing the processor to execute the following functions. Asignaling function permits the ShareMachine computer to discoverparticipating elements, such as gateway mobile stations. A SuperHeadcommunication function enables communication with a SuperHead computer(in XML over HTTPS, for example). An optional configuration/reportingfunction enables configuration of the ShareMachine computer and trafficstatistics reporting via a user interface, which may be a local userinterface or a remote user interface. A packet management functionperforms packet packing/unpacking and multiplexing/demultiplexing aswell as NAT/NAPT (Network Address (and Port) Translation) operations. ADNS function permits the ShareMachine computer to participate in DNSoperations with pre-existing internet-based DNS servers.

FIG. 4 shows a block diagram of a service coordination server,colloquially called a SuperHead computer and denoted by reference signSH. The purpose of the SuperHead computers is to coordinate the servicesof the ShareMachine computers SM. As regards a functional description ofthe hardware blocks, which are denoted by reference numerals 305 through330, the SuperHead computer SH can be similar to the ShareMachinecomputer SM shown in FIG. 3, and the description of the hardwareelements will not be repeated. It is the SuperHead software application370 that makes the SuperHead computer SH perform the following inventivefunctions.

A ShareMachine communication function enables communication withShareMachine computers (in XML over HTTPS, for example). A ShareMachinemanagement function enables keeping track of ShareMachine computers andprioritization of them according to various operating parameters and IPaddresses, which are to be communicated to Gateway Mobile Stations. Anoptional configuration/reporting function enables configuration of theSuperHead computer and traffic statistics reporting via a userinterface, which may be a local user interface or a remote userinterface.

FIG. 5 is a signaling diagram illustrating a gateway establishment in ascenario which comprises a WLAN client terminal, a mobile stationconfigured as a gateway, a DNS server and an internet host. FIG. 5depicts an illustrative scenario involving a client terminal CT and amobile station which supports a gateway application according to thepresent invention. In step 5-0 the inventive gateway application isexecuted in the mobile station. The execution of the gateway applicationis typically started in response to a user instruction via the mobilestation's user interface. In a typical implementation, the mobilestation receives user interface navigation instructions to“Applications” from which the inventive gateway application is selectedfor execution. One of the acts performed by the mobile station'sprocessor, under control of the inventive gateway application, is toensure that the WLAN circuitry of the mobile station is operational. Thesignificance of step 5-0, and of the corresponding deactivation step5-40, is that the mobile station is only reserved for wireless broadbandgateway applications for a user-specified time, and at other times themobile station can perform whatever tasks required by its user.

In step 5-2 the gateway application instructs the mobile station'sprocessor to prepare an ad-hoc WLAN network around the mobile station,by acting as a WLAN base station (as opposed to the mobile station'smore conventional usage as a WLAN client). In step 5-4 the gatewayapplication instructs the mobile station to initiate broadcasting of abeacon ID message, which typically is an IBSSID message as defined instandard IEEE 802.11x. Step 5-4 is depicted as an arrow, but in practicethe broadcasting of the beacon ID message should be repeated until step5-40 in which the execution of the gateway application is terminated.

In step 5-6 the client terminal CT searches for available WLAN networksand detects the broadcasted beacon ID and selects the WLAN networkcreated by the mobile station MS. In step 5-8 the client terminal CT, aspart of a conventional WLAN attach procedure, requests an IP addressfrom the mobile station's WLAN base station, which returns the requestedIP address in step 5-10. Dynamic Host Configuration Protocol (DHCP) istypically used for steps 5-8 and 5-10.

Let us assume that the client terminal CT tries to retrieve a web pagefrom the internet host (item 190 in FIG. 1). In step 5-12 the clientterminal CT sends a domain name service (DNS) query for the IP addressof the host's web page to the DNS server of the mobile station's gatewayapplication. In step 5-14 the mobile station's gateway applicationforwards the DNS query to internet's domain name service and obtains thehost's IP address in step 5-16. In step 5-18 the mobile station'sgateway application returns the host's IP address to the client terminalCT.

In step 5-20 the client terminal CT requests a web page from the host'sIP address. Hypertext Transfer Protocol (HTTP) is typically used forthis purpose. This request, like any communication between the clientterminal CT and any internet hosts, takes place via the inventivegateway application being executed in the mobile station.

Step 5-22 is an optional step which may be omitted in some embodiments.When performed, step 5-22 comprises redirecting the first HTTP pagerequest from client terminal CT to another internet host, called Host′.This means that in step 5-24 the gateway application forces the clientterminal's first HTTP page request to a forced home page at the IPaddress of Host′. For example, the operator of the site Host′ maydisplay advertisements in exchange of sponsoring communication costsover the access network AN. In step 5-26 the web site Host′ returns therequested web page, which the gateway application relays to the clientterminal CT in step 5-28.

In step 5-30 the client terminal CT again requests the web page from thehost's IP address. Since this the second (or further) page request fromthe client terminal, the gateway application no longer redirects theHTTP request but relays it to the Host in step 5-32. In steps 5-34 and5-36 the requested web page from the Host is transmitted to the clientterminal. As shown by arrow 50, the process can return from step 5-36 tostep 5-20 when future web pages are requested. The loops 5-30 through5-36 can be repeated until the gateway application is terminated in step5-40. If the forced home page feature (step 5-22) is not implemented,the first HTTP request (step 5-20) is processed similarly to thesubsequent HTTP requests (step 5-30). In subsequent executions of step5-30, if the HTTP page request relates to a web page for which thegateway application does not have an IP address, a DSN query will beperformed (cf. steps 5-14 and 5-16).

FIG. 5 also shows an additional client terminal, denoted CT′. Steps 5-6through 5-36 will be repeated for each additional client terminal. Thismeans that by virtue of the inventive gateway application, whichinstructs the mobile station MS to act as a WLAN base station (asopposed to a WLAN client), the mobile station MS can support anarbitrary number of client terminals which act as WLAN client terminalsand which, by virtue of the authentication performed by the mobilestation, can share a single subscription to the access network.

FIG. 5 and the foregoing description of it illustrate use of HTTPprotocol. The inventive gateway application supports other protocols inan analogous manner and assigns a specific port number to each supportedprotocol. For instance, the gateway application can instruct the mobilestation to convey encrypted HTTPS traffic by utilizing the ProxyConfiguration field of HTTPS protocol.

FIG. 6 is a signaling diagram illustrating IP address discovery and DHCPoperation, which involves a WLAN client terminal CT, a master mobilestation MS1 and a slave mobile station MS2. Both mobile stations MS1 andMS2 execute the inventive gateway application 270 (see FIG. 2),including the functions 272 and 274. In a typical implementation, themobile stations MS1 and MS2 and their gateway applications areidentical. The mobile station that first establishes the ad-hoc WLANnetwork, as described in connection with FIGS. 1 and 5, becomes themaster mobile station MS1, and any subsequent mobile stations that jointhe ad-hoc WLAN network afterwards will assume the role of a slavemobile station. For the interest of clarity, FIGS. 6 through 8 only showone slave mobile station MS2, but the invention and its embodiments arescalable to any reasonable number of mobile stations. For the interestof brevity, the words “mobile station” may be omitted and the master andslave mobile stations may be referred to as “master” and “slave”.

In step 6-2 the client terminal CT requests an IP address from themaster MS1 in an DCHP Discover( ) procedure. In step 6-4 the master MS1sends the client terminal CT the requested IP address. In the presentexample, the master MS1, whose own IP address of is 192.168.1.1, offersthe client terminal the next available IP address, which is 192.168.1.2.In step 6-6 the mobile station MS2, having detected that an ad-hoc WLANnetwork already exists, requests an IP address from the master MS1. Inthe example shown, the master MS1 grants in step 6-8 the slave MS2 an IPaddress of 192.168.2.1, which in this example is derived from themasters' own IP address by setting the third octet to the next availablenumber. In other words, the slave mobile station MS2 is assigned asubnet of its own. This implementation provides certain benefits asregards optimization of resource utilization. For instance, the slavemobile station MS2 may act as a WLAN gateway to some of the clientterminals, whereby it is not necessary to route all traffic via themaster mobile station MS1.

It should be noted that in a typical environment the IP address leasetime cannot be very long because the ad-hoc network does not indicatewhen a slave mobile station leaves the network. After a mobile stationleaves the network, the gateway and subnet addresses should be renewedquickly. In a typical environment, in which the mobile stations are notdedicated to gateway service, the IP lease time is preferably no morethan a few minutes.

FIG. 7 is a signaling diagram illustrating a flow of data packets from aWLAN client terminal CT to an internet host via a master mobilestation/gateway MS1, a slave mobile station/gateway MS2 and aShareMachine computer SM. In the initial state 7-0, an ad-hoc WLANnetwork (item WN in FIG. 1) has been established and a DHCP discoveryprocedure has been performed, as described in connection with thepreceding FIGS. 5 and 6. In the embodiment described herein, the ad-hocWLAN network comprises a master gateway mobile station MS1 and a slavegateway mobile station MS2, but the client terminal CT only communicateswith the master MS1.

In steps 7-2 and 7-4 the client terminal CT sends two IP packets IP1 andIP2 to the master MS1. The ultimate destination of the IP packets is theinternet Host HO. The master MS1 thus acts as the client terminal's onlyaccess point to the internet. In step 7-6 the master MS1 sends the firstIP packet IP1 as an UDP packet to the ShareMachine computer SM. Anyintervening access networks are omitted for clarity, but they are shownin FIG. 1. In step 7-8 the master MS1 multicasts the second IP packetIP2 as an UDP packet, and the slave MS2 captures the multicasttransmission. In step 7-10 the slave MS2 sends the second IP packet IP2as an UDP packet to the ShareMachine computer SM. In steps 7-12 and 7-14the ShareMachine computer SM sends the IP packets IP1 and IP2 to theHost. In the example described herein, UDP packets were used forefficiency's sake. If better robustness is desired and some efficiencycan be sacrificed, TCP protocol may be used instead.

For the purposes of FIGS. 7 and 8, it suffices that the master gatewaymobile station MS1 somehow knows or obtains the address of theShareMachine computer SM. For instance, in a simple implementation themaster MS1 or its user may utilize an internet search engine to discoveraddresses of available ShareMachine computers. An enhanced procedure forobtaining the ShareMachine computer's address from a SuperHead computerwill be described in connection with FIG. 9.

The reason for using multicast over point-to-point transmission is thatSymbian.RTM. S60 or S80 platforms, which a large portion of current WLANequipped mobile stations are based on, do not provide an ApplicationProgramming Interface (API) function to access the Media Access Control(MAC), or device hardware, layer by individual packets. Resorting to themulticast transmission in the WLAN network provides a workaroundsolution for this problem.

In one specific implementation the overhead due to multitasking isreduced by setting a flag in the first (master) mobile station/gateway,such that the slave mobile stations/gateways do not have to unpack eachpacket to see its destination. The multitasking operation alsocompensates for the fact that packet loss is a definite handicap inmobile access networks. As a result of the multicast transmission viamultiple alternative routes, the likelihood of at least one successfulpacket delivery is increased. In addition, the multitasking operationincreases robustness of the ad-hoc WLAN network. If one of the slavemobile stations/gateways disappears from the WLAN network, the packetsmay still survive.

In the scenario shown in FIG. 7, the master MS1 sends the first IPpacket IP1 to the ShareMachine computer SM directly, while the second IPpacket IP2 is sent via the slave MS2. The next IP packet (not shown)will be sent directly again, and so on, in order to achieve loadbalancing among the gateways MS1, MS2 and the access networks AN1, AN2(see FIG. 1). It is possible that, as a result of the overhead caused bysending some packets via the slave(s) and/or varying delays in theaccess networks, the ShareMachine computer SM receives some packets outof sequence, and packet IPn will be received after packet IPn+1. Thusthe ShareMachine computer SM should be able to buffer packets coming outof sequence until it has received all the packets it needs to forwardthem to the Host in the correct sequence. The ShareMachine computer SMmay employ a protocol watchdog timer that raises an alert if some packetis not received for a predetermined period of time, in which case theShareMachine computer SM may request retransmission of the packetsstarting from the last properly received packet.

In steps 7-16 through 7-28, two internet packets IP3 and IP4 are sentfrom the Host, via the ShareMachine computer SM and the gateways MS1,MS2, to the client terminal CT. Based on the preceding the descriptionof the reverse direction, the packet transmission from the Host to theclient terminal CT is mostly self-explanatory and a detailed descriptionis omitted. In this case the slave MS2 must send the packet IP4 overmulticast transmission to the master MS1, and it is the task of themaster MS1 to assemble the packets in the correct sequence, byrequesting retransmission if necessary.

The embodiment described herein provides the benefit that the operationof the inventive scalable gateway is completely transparent to theclient terminal CT and the Host, which need no modifications whatsoeverand which can only detect an increased transmission speed.

FIG. 8 is a more detailed signaling diagram illustrating data flow froma WLAN client terminal CT to an internet host HO via a master gatewaymobile station MS1, a slave gateway mobile station MS2 and aShareMachine computer SM. In the present embodiment, the ShareMachinecomputer comprises a Network Address Translation block, which is alsocapable of Port Translation, as well as the corresponding reversetranslations. In the present context, this block is called a NetworkAddress & Port Translation block NAPT. Because the NAPT block changesthe IP addresses, it is shown as a distinct network element, although inpractice it may be, and typically is, an integral functional block ofthe ShareMachine computer SM. The NAPT block may utilize the packets'port numbers to identify the source and destination addresses and toseparate the packets based on the addresses.

As shown near the top of FIG. 8, the primary IP address assigned to thenetwork elements CT, MS1, MS2, SM and HO are denoted by a suffix “IP”after the reference sign of the respective network element. For example,CT IP is the IP address assigned to the client terminal CT. The masterand slave gateway mobile stations MS1 and MS2 also employ a secondary IPaddress each, and these are denoted with a prime after the “IP” suffix.For example, MS1 IP′ is the secondary IP address assigned to the mastergateway mobile station MS1. The secondary IP addresses of the mobilestations are used for the communication between the mobile stations MS1,MS2 and the ShareMachine computer SM. In one representativeimplementation, the mobile stations' primary IP addresses MS1 IP and MS2IP are assigned from the subnetwork of the master mobile station MS1,while the secondary IP addresses MS1 IP′ and MS2 IP′ are public IPaddresses assigned by the mobile stations' respective access networkoperators.

In the initial state 8-0, an ad-hoc WLAN network has been establishedand a DHCP procedure has been performed. The remaining steps of FIG. 8constitute four major phases, which are transmitting a first packet 1Uand a second packet 2U from the client terminal CT to the host HO(called uplink transmission) and transmitting a first packet 1D and asecond packet 2D from the host HO to the client terminal CT. Addressingdetails of the messages and operations shown in FIG. 8 are compiled intotable 1.

Steps 8-11 through 8-17 relate to the transmission of the first uplinkpacket 1U from the client terminal CT to the host HO. In step 8-11 theclient terminal CT sends the packet 1U to the master mobile station MS1.As shown in Table 1, the packet 1U is an Ethernet packet over the WLANnetwork established by the master mobile station MS1. The source anddestination addresses of the packet 1U are the MAC addresses of themaster mobile station MS1. The packet's payload contains IP Data, astransmitted by the client terminal. Table 1 also contains a second rowentry for the step 8-11, and this means that there is an IP packetencapsulated within the Ethernet packet. The IP packet's source anddestination addresses are the IP addresses of the client terminal CT andhost HO, respectively. Step 8-12 is an optional header packing step, thepurpose of which is to optimize the use of the radio interfacebandwidth. In the scenario shown in FIG. 8, the master mobile stationMS1 does not send the first packet 1U directly to the ShareMachinecomputer SM but via the slave mobile station MS2. Accordingly, step 8-13comprises sending the packet 1U as a multicast transmission, whichinvolves sending from the MAC address of MS1 an Ethernet packet intowhich is encapsulated an UDP packet. The UDP packet, in turn, containsthe actual IP packet, as shown in Table 1. The slave mobile station MS2,having received the multicast transmission, sends the UDP packet to theIP address of the ShareMachine computer SM in step 8-14. The headerunpacking step 8-15 reverses the effect of the header packing step 8-12.In step 8-16 the NAPT block of the ShareMachine computer SM performsNetwork Address Translation on the packet 1U. After the Network AddressTranslation, in step 8-17, the ShareMachine computer SM sends the firstuplink packet 1U to the host HO.

Steps 8-21 through 8-27 relate to the transmission of the second uplinkpacket 2U from the client terminal CT to the host HO. The transmissionof the second uplink packet 2U is simpler than the transmission of thefirst uplink packet 1U in that the packet 2U is sent directly from themaster mobile station MS1 to the ShareMachine computer SM, and themulticast transmission over the WLAN is omitted. The transmission ofpackets originating or terminating at the client terminal CT and host HOis similar regardless of whether or the packet is conveyed via the slavemobile station MS2. This means that the transmission is transparent tothe client terminal CT and host HO, which can only detect an improvedtransmission bandwidth.

Steps 8-31 through 8-37 relate to the transmission of the first downlinkpacket 1D from the host HO to the client terminal CT. Finally, steps8-41 through 8-47 relate to the transmission of the second downlinkpacket 2D from the host HO to the client terminal CT. A detaileddescription of the various transmissions is omitted as the downlinktransmission is analogous with the uplink transmission, and thenecessary addressing details are indicated in Table 1. In the embodimentdescribed herein, the mobile stations' public (operator-assigned) IPaddresses are used for communicating with the ShareMachine computer SM,while private IP addresses, i.e., those assigned by the master mobilestation MS1, are used for communicating between the mobile stations.

TABLE 1 Addressing details relating to FIG. 8 Step Packet SourceDestination Data Note 8-11 Ethernet Packet CT MAC MS1 MAC IP Data IPPacket CT IP HO IP IP Data 8-13 Ethernet Packet MS1 MAC Multicast UDPPacket UDP Packet MS1 IP Multicast IP Packet 8-14 UDP Packet MS2 IP′ SMIP IP Packet 8-16 IP Packet CT IP HO IP IP Data Id by MS public IP 8-17IP Packet SM IP HO IP IP Data Unique Source port 8-21 - - - See8-11 - - - IP Packet CT IP HO IP IP Data 8-23 UDP Packet MS1 IP′ SM IPIP Packet 8-26 - - - See 8-16 - - - 8-27 - - - See 8-17 - - - 8-31 IPPacket HO IP SM IP IP Data Unique Dest'n port 8-32 IP Packet HO IP CT IPIP Data Id by MS public IP 8-34 UDP Packet SM IP MS2 IP′ IP Packet 8-35UDP Packet MS2 IP Multicast IP Packet 8-37 IP Packet HO IP CT IP IP DataEthernet Packet MS2 MAC CT MAC IP Data 8-41 - - - See 8-31 - - -8-42 - - - See 8-32 - - - 8-44 UDP Packet SM IP MS1 IP′ IP Packet8-47 - - - See 8-37 - - -

In the above table, the expressions “unique source/destination port”means that the ShareMachine computer SM may identify various connectionsto the same host HO by means of port numbers. For instance, theShareMachine computer SM may identify a connection from an exemplaryclient terminal CT to the host HO by port number 5555, while the nextconnection will be identified by port number 5556 (or any other uniquevalue). When the host HO sends packets downstream, the ShareMachinecomputer SM can use the port number to determine which connection thedownstream packets belong to.

FIG. 9 discloses a procedure that the master mobile station may utilizeto discover a serving SuperHead and ShareMachine computers. Step 9-2comprises initialization of the gateway application in the mastergateway mobile station MS1, as described in connection with FIGS. 1, 2,5 and 6. In step 9-4 the master MS1 retrieves a list of SuperHeadcomputers from its memory. The installation of the gateway applicationinto the master MS1 may store a default SuperHead list, and this listwill be updated on subsequent executions of the gateway application. Instep 9-6 the master MS1 selects the first SuperHead computer addressfrom the list. In step 9-8 the master MS1 sends an inquiry to theselected SuperHead computer address. Step 9-10 involves a test as towhether a response to the inquiry was received from the selectedSuperHead computer address. If the test is successful, the processproceeds to step 9-12, in which the master MS1 begins to use one or moreof the obtained ShareMachine addresses. In step 9-14 the master MS1stores the list of SuperHead addresses.

On the other hand, if the test in step 9-10 fails, the process proceedsto steps 9-16 and 9-18, in which the next SuperHead address from thelist is tried. If the list of SuperHead addresses is exhausted, theprocess proceeds to step 9-20 and 9-22, which involve various useralerting steps and/or error recovery procedures. For instance, themaster mobile station MS1 or its user may employ an internet searchengine to obtain more SuperHead addresses.

A proper response from the SuperHead computer to the master MS1 shouldinclude a list of IP addresses of one or more available ShareMachinecomputers and, preferably, an updated list of available SuperHeadcomputers. In a representative but non-restrictive implementation, suchlists are sent in XML (eXtendible Markup Language) format. Reception ofthe list of available ShareMachine computers permits the master MS1 toknow computers have reported themselves to the SuperHead computer aspotential ShareMachine computers.

Typically each connection is served by one ShareMachine computer, butone master MS1 may serve several connections from one or more clientterminals, and each connection may be served by a different ShareMachinecomputer. Also, it is beneficial if the master MS1 obtains and stores alist of several ShareMachine addresses, in case the active ShareMachinecomputer detaches itself from service or otherwise ceases to serve theconnection.

In some embodiments the SuperHead and ShareMachine computers areimplemented in a distributed manner. Such distributed implementationproves certain advantages, in addition to capacity considerations. Forinstance, many internet services or servers are threatened by networkvandalism or sabotage, such as denial-of-service attacks. Furthermore,while there is nothing illegal in the usage of the access networksubscription in the mobile stations, the inventive distribution of theaccess network subscriptions among several client terminals may resultin access network traffic which is heavier than average, and the networkoperators may be tempted to prevent or obstruct the operation of theinventive gateway applications in the mobile stations. A distributedimplementation of the SuperHead and ShareMachine computers makes themless vulnerable to such network-based vandalism by hackers orobstructions by access network operators. Robustness may be furtherimproved by utilizing dynamic IP addresses for the SuperHead and/orShareMachine computers.

In an enhanced implementation of the procedure shown in FIG. 9, thelists of SuperHead and ShareMachine computers are updated regularly, viainquiries to a SuperHead computer. Frequent updating of the SuperHeadand ShareMachine addresses provide further robustness, particularly incases where the SuperHead and/or ShareMachine computers are conventionalhome computers whose spare time is being utilized to serve connection inthe manner described herein. When such home computers are turned off orused for other purposes, they stop operating as SuperHead and/orShareMachine computers. Accordingly, the address updating frequencyshould be dimensioned based on representative operating patterns oftypical home computers, with 10 minutes being a good starting value.While the SuperHead discovery procedure shown in FIG. 9 has beendescribed in connection with a master mobile station MS1, thecorresponding SuperHead discovery procedure may also be utilized byShareMachine computers, with the variation that the ShareMachinecomputer registers itself with the discovered SuperHead computer as soonas it has discovered one.

In a variation of the address inquiry procedure described herein, thefunctions of the SuperHead and ShareMachine computers are combined insuch a manner that the ShareMachine computers keep track of one another.In other words, the ShareMachine computers also act as SuperHeadcomputers.

The previously described embodiments relate to provision of a scalablegateway functionality. One of the key elements of the invention isestablishment of a WLAN access point in a mobile station. Byestablishing a WLAN access point in the mobile station, it will bepossible to utilize some of the enhanced functionality of modern mobilestations.

In addition to merely conveying internet traffic between the clientterminal CT and the internet host, the inventive gateway applicationcan, in some specific embodiments, provide additional or supplementaryservices which utilize some of the functionality of modern mobilestations. In some implementations, such supplementary services areprovided by an arrangement in which a supplementary server enhances theservice(s) provided by a primary server. Such a supplementary server canbe part of the functionality of the inventive WLAN gateway application,or it can be implemented as a network element distinct from the primaryserver.

One exemplary implementation of such additional services involvesutilization of GPS (Global Positioning System) devices incorporated intosome mobile stations. The inventive gateway application may be enhancedto associate GPS-provided geographical coordinates to the trafficoriginated by the client terminal, or to some of that traffic. Forinstance, the gateway application can tag still or video image data withgeographical coordinates and/or use some additional service (not shownseparately) that maps with geographical coordinates to a plaintext nameof the relevant location. In another implementation the gatewayapplication associates GPS-provided coordinates to the traffic, or someof it, while the actual tagging of the images with the coordinates isprovided by some additional server, such as an image sharing server (notshown separately). Actually, what matters is the location of the clientterminal and not the location of the mobile station acting as a WLANgateway. But considering the short range of the mobile station's WLANtransmission, the mobile station's location can be used as the clientterminal's location for virtually all practical purposes.

In a more ambitious implementation, the gateway application can provideadditional services on the basis of the geographical coordinates. Forinstance, the gateway application can recognize various queriesinitiated by the client terminal and/or responses to those queries byinternet servers and enhance the query responses by relevant map orphotography information. For instance, the gateway application candetect a query to “post” and provide the query response with a mapand/or photograph of the post office closest to the mobile station'sGPS-provided geographical coordinates. In order to obtain the map and/orphotograph, the gateway application may query a supplementary serverwhich provides the requested functionality.

Another example of such additional services relates to trafficstatistics which the gateway application collects and transmits to someinternet-based supplementary server (not shown separately). For example,such a supplementary server may use the traffic statistics to monitorQuality of Service (QoS) parameters, which can be used to maintain theQoS at a specified level and/or to optimize resource usage in the accessnetwork. In some embodiments the supplementary server is an advertisingserver. The advertising server may utilize the traffic statistics fortargeted or tailored advertising to the client terminal CT. Such trafficstatistics may include, for example, user identification, usage (amountof traffic, usage times, internet addresses visited, query parameters,or the like). Alternatively or additionally, the gateway application cantransmit traffic statistics to a billing server which participates incharging the client terminal's subscriber. Yet further, the advertisingserver and the billing server may cooperate in such a manner that theadvertising server's operator sells advertisement space or time and theadvertising server credits the client terminal's subscriber for anyadvertisements received. The credits are then relayed to and used by thebilling server in order to reduce the client terminal's subscriber'sinvoice, generate additional services, extend pre-paid subscriptiontime, to name just a few examples.

Finally, the gateway application may be configured to convey the mobilestation's location, or some derivative it, to the advertising server fortargeted or tailored advertising on the basis of the mobile station'slocation. For instance, targeted advertising for some goods or servicemay include sending an advertisement to a client terminal only if themobile station's location indicates that the client terminal isreasonably close to the outlet of the goods or service. On the otherhand, tailored advertising may be implemented such that theadvertisement indicates the address or location of the closest outlet.

FIGS. 10 and 11 illustrate some exemplary embodiments in which thepresent invention benefits from the functionality of modern mobilestations, such that the resulting WLAN gateway is functionally superiorto dedicated WLAN access points. FIG. 10 shows an embodiment in whichthe WLAN circuitry, and optionally the WLAN gateway application, in themobile station MS is activated periodically to detect possible WLANclient terminals CT nearby. In one representative scenario, aWLAN-capable digital camera acts as a WLAN client terminal. In theembodiment shown in FIG. 10, the mobile station MS employs two timerswhich may be realized by means of software-implemented tick counters, asis well known to those skilled in the art. One of the timers is called asleep timer while the other is called a watchdog timer. The sleeptimer's function is to periodically wake up the mobile station's WLANcircuitry, and optionally the WLAN gateway application. The watchdogtimer is used to detect non-activity periods of predetermined length inthe WLAN network so that the WLAN circuitry can be powered off in orderto optimize battery re-sources.

In step 10-1 the WLAN circuitry of the mobile station MS is powered offand the execution of the WLAN gateway application may be suspended orterminated. Step 10-1 terminates when the sleep timer expires. Forinstance, the sleep timer may generate a processor interrupt whichdirects the mobile station's processor to perform program routines foractivating the WLAN circuitry and starting or resuming execution of theWLAN gateway application. After step 10-2 the mobile station hasestablished a WLAN network. In step 10-3 the mobile station checks ifany client terminal(s), such as the exemplary digital camera, attempt(s)to attach to the WLAN network. If not, the process proceeds to step10-8, in which the WLAN network and circuitry are deactivated and theprocess begins anew at step 10-1. On the other hand, if any clientterminal attaches to the WLAN network, the mobile station starts awatchdog timer in step 10-4 and maintains the WLAN network as indicatedin step 10-5. Step 10-6 includes a test to detect client terminalactivity. If client terminal activity is detected, the process returnsto step 10-4 in which the watchdog timer is restarted. Naturally, anyclient-related requests are served as well, as part of the basicfunctionality of the WLAN gateway application. On the other hand, if noclient terminal activity is detected, the process proceeds to step 10-7which is a test as to whether the watchdog timer has expired. If not,the process returns to step 10-5 in which the WLAN network is maintainedwithout restarting the watchdog timer. Eventually, a moment occurs whenno client activity has been detected and the watchdog timer expires, andthis is detected in step 10-7. Then, in step 10-8, the WLAN network andcircuitry are deactivated and the process begins anew at step 10-1.

By virtue of the embodiment described in connection with FIG. 10, theWLAN gateway application may terminate its own execution and power offthe mobile station's WLAN circuitry. The automatic execution of thegateway application and the accompanying automatic activation of themobile station's WLAN circuitry provides certain benefits. For instance,both digital cameras and mobile stations are handicapped by small userinterfaces and relatively short battery life, particularly when theirliquid-crystal displays (LCD) are illuminated. The automation describedin connection with the present embodiment alleviates such handicaps.

FIG. 11 shows an embodiment in which the mobile station'slocation-determination functionality is used to enhance image uploadingto an image hosting server. In step 11-0 a WLAN connection isestablished between the gateway application being executed in the mobilestation MS and the WLAN-equipped digital camera CAM acting as a clientterminal CT. For details of the WLAN connection establishment areference is made to FIGS. 5 and 10. In step 11-2 the camera CAM/CTinitiates a DNS inquiry to obtain the internet ad-dress of the imagehosting server. In step 11-4 an embodiment of the gateway applicationbeing executed in the mobile station MS detects that the cam-era/clientterminal CAM/CT executes a location-aware application. Accordingly, thegateway application uses the mobile station's location-determinationfunctionality to determine the mobile station's location. For instance,the mobile station's location may be determined on the basis of themobile station's built-in satellite-positioning device (GPS) or on thebasis of cell ID determination in the access networks. In an optionalstep 11-8, the gateway application sends the mobile station's locationto an embodiment of the supplementary server SS, which in this scenarioreceives the mobile station's location and returns a plaintext-formattedlocation description. For instance, the geographical coordinates or cellID of Piccadilly Circus might be converted to a plaintext description of“Piccadilly Circus, London”. In step 11-10, the camera/client terminalCAM/CT begins uploading of image data to the image hosting server. Instep 11-12 the gateway application complements the image data with themobile station's location. In one particular implementation, thelocation data is placed in a metadata field of the image(s).

It is readily apparent to a person skilled in the art that, as thetechnology advances, the inventive concept can be implemented in variousways. The invention and its embodiments are not limited to the examplesdescribed above but may vary within the scope of the claims.

REFERENCES

FI20080032, filed Jan. 16, 2008, and

PCT/FI2008/050617, filed Oct. 30, 2008.

Both references are commonly owned patent applications whose contentsare incorporated herein by reference. Reference 2 is an unpublishedapplication at the filing date of the present invention, which is whysome sections of its contents are repeated here.

1. An communication device providing network access over a wirelesslocal area network (WLAN) for a WLAN client terminal with a secondelectronic device, the communication device comprising: a processorconfigured to: establish a WLAN; activate the WLAN; receive, from theWLAN client terminal via the WLAN, a first data packet including addressinformation of a internet host; forward the first data packet to thesecond mobile station via the WLAN; and instruct the second mobilestation to send the first data packet to the internet host according tothe address information.
 2. The communication device according to claim1, the processor further configured to establish a connection with amobile network wherein the processor is further configured to: receive asecond data packet including the address information of the internethost from the WLAN client terminal via the WLAN; and send the seconddata packet to the internet host via the connection with the mobilenetwork according to the address information.
 3. The communicationdevice according to claim 2, wherein the address information includes anInternet Protocol (IP) address of the internet host.
 4. Thecommunication device according to claim 1, wherein the first data packetis forwarded to the second mobile station by sending the first datapacket in multicast transmission.
 5. The communication device accordingto claim 4, wherein the first data packet is forwarded as a UserDatagram Protocol (UDP) packet.
 6. The communication device according toclaim 1, wherein the processor is further configured to: receive arequest for an Internet Protocol (IP) address over the WLAN from theWLAN client terminal; assign an IP address to the WLAN client terminal,wherein the IP address assigned to the WLAN client terminal is derivedfrom the mobile station's own IP address by setting the fourth octet toan available number; receive a request for an IP address over the WLANfrom the second mobile station; and assign an IP address to the secondmobile station, wherein the IP address assigned to the second mobilestation is derived from the mobile station's own IP address by settingthe third octet to an available number.
 7. The communication deviceaccording to claim 1, wherein the processor is further configured to:receive a third data packet targeting the WLAN client terminal forwardedby the second mobile station via the WLAN; receive a fourth data packettargeting the WLAN client terminal transmitted via the connection withthe mobile network; assemble the third data packet and the fourth datapacket in a correct sequence; and send the third data packet and thefourth data packet to the WLAN client terminal via the WLAN, wherein thethird data packet and the fourth data packet are from the internet host.8. A method executed by a communication device for providing networkaccess over a wireless local area network (WLAN) to a WLAN clientterminal, the method comprising: establishing a WLAN; receiving, fromthe WLAN client terminal via the WLAN, a first data packet includingaddress information of a internet host; forwarding the first data packetto a second mobile station via the WLAN; and instructing the secondmobile station to send the first data packet to the internet hostaccording to the address information.
 9. The method according to claim8, further comprising: establishing a connection with a mobile network;receiving a second data packet including the address information of theinternet host from the WLAN client terminal via the WLAN; and sendingthe second data packet to the internet host via the connection with themobile network according to the address information.
 10. The methodaccording to claim 9, wherein the address information includes anInternet Protocol (IP) address of the internet host.
 11. The methodaccording to claim 8, wherein the first data packet is forwarded to thesecond mobile station by sending the first data packet in multicasttransmission.
 12. The method according to claim 11, wherein the firstdata packet is forwarded as a User Datagram Protocol (UDP) packet. 13.The method according to claim 8, further comprising: receiving a requestfor an Internet Protocol (IP) address over the WLAN from the WLAN clientterminal; assigning an IP address to the WLAN client terminal, whereinthe IP address assigned to the WLAN client terminal is derived from themobile station's own IP address by setting the fourth octet to anavailable number; receiving a request for an IP address over the WLANfrom the second mobile station; and assigning an IP address to thesecond mobile station, wherein the IP address assigned to the secondmobile station is derived from the mobile station's own IP address bysetting the third octet to an available number.
 14. The method accordingto claim 8, further comprising: receiving a third data packet targetingthe WLAN client terminal forwarded by the second mobile station via theWLAN; receiving a fourth data packet targeting the WLAN client terminaltransmitted via the connection with the mobile network; assembling thethird data packet and the fourth data packet in a correct sequence; andsending the third data packet and the fourth data packet to the WLANclient terminal via the WLAN, wherein the third data packet and thefourth data packet are from the internet host.